In many print applications special media are used to provide improved image clarity, colors and durability over generic media. Often these media include special layers applied to raw base paper to achieve these improvements.
For example, photographic inkjet media belonging to conventional silver halide photographic quality generally include a photo base of resin-coated raw base paper. The resin is applied to the raw base paper by hot melt extrusion. In hot melt extrusion one or more polymeric materials are heated to or above their melting point and applied in a uniform coating on the raw base paper.
An ink-receiving layer together with other functional layers is deposited on top of the photo base by a wet coating process. In the wet coating process, a uniform and continuous wet film must be applied to the photo base. Then water or solvent must be removed from the coating by the drying process.
Energy and time requirements, in addition to technical complexity, often make the wet coating process very costly. Furthermore, the wet coating process may introduce more product defects than other aspects of the media fabrication process.